Quick-release jaws with a single-piece bearing chuck

ABSTRACT

A workholding chuck can use actuating members that pivot within a non-split unitary front bearing. The non-split unitary front bearing can include pockets in its central bore that can allow a spherical section of an actuator arm to be inserted into the bearing. The spherical section can include radially recessed areas to facilitate the insertion into the bearing. The jaws can be retained to the actuator arms through the use of a quick-release assembly. The quick-release assembly allows the jaws to easily and quickly be changed to allow the chuck to grasp different workpieces.

FIELD

The present disclosure relates to a workholding chuck assembly for usein machining applications, and more specifically to a workholding chuckthat can use single-piece bearings and quick-release jaws.

BACKGROUND

The statements in this section merely provide background informationrelated to the present disclosure and may not constitute prior art.

An adjustable chuck of the type in widespread use for grippingworkpieces of different sizes typically includes a plurality of jawsthat is radially movable to grip and release a workpiece. The jaws aretypically configured for retaining a specific workpiece; and when it isdesired to use the chuck to grip different workpieces, different jawsare used. Accordingly, when it is desired to machine a differentworkpiece, the jaws on the chuck must be changed, which is a timeconsuming process.

Typically, the jaws of a chuck are attached to actuators that arelocated within a bearing that allows the actuators to pivot and move thejaws radially inwardly and outwardly to engage with and release theworkpiece. The bearings are fractured into two pieces for assemblypurposes. The use of fractured bearings, however, has drawbacks. Forexample, the two bearing halves must always be kept together in setsthroughout the life of the bearing. Additionally, the fracture creates agap in the bearing interface that allows grease to escape from insidethe bearing during movement of the actuator. This, in turn, affects theefficiency and longevity of the bearing, actuator and, accordingly, thechuck. Moreover, the fracture can enable the bearing pieces to moveslightly relative to one another as the chuck is actuated. The relativemovement can affect the accuracy of the load imparted by the jaws ontothe workpiece.

SUMMARY

A workholding chuck assembly according to the present disclosure uses anon-split unitary bearing having a bore therethrough to pivotally retainan actuator arm within a housing. The actuator arm can include asemi-spherical section that can fit within the bore of the non-splitunitary bearing. The bearing bore can have an engaging surface thatengages with the semi-spherical surfaces and can also include at leasttwo radially recessed pockets. One end of the actuator arm can receive aworkpiece retaining jaw thereon, while another end of the actuator armcan be coupled to an actuator that can drive pivotal movement of theactuator arm in the bearing to retain and release a workpiece.

In another aspect of the present disclosure, a workholding chuckassembly includes a quick-release assembly that has at least oneretaining member operable to selectively secure a jaw to, and allowremoval of the jaw from, an actuator arm. The quick-release assembly canallow the removal and securing of the jaw through non-removing movementof a component of the quick-release assembly that is coupled to theretaining member.

In another aspect of the present disclosure, a workholding chuckretro-fit kit includes an actuator arm and a non-split unitary bearing.The bearing has a bore therethrough with an engaging surface that canengage with a semi-spherical section of the actuator arm such that theactuator arm can pivot within the bore of the bearing.

In still another aspect of the present disclosure, a workholding chuckretro-fit kit includes a quick-release assembly operable to selectivelysecure a jaw to, and allow removal of a jaw from, a first end portion ofan actuator arm. The quick-release assembly allows the securing andremoval through non-removing movement of a component of thequick-release assembly that is coupled to the retaining member.

Thus, the present disclosure includes a non-split unitary bearing thatcan be used to pivotally retain an actuator arm in a workholding chuckassembly. The non-split unitary bearing can reduce the escaping ofgrease from the bearing. The non-split nature of the unitary bearing canimprove the repeatable accuracy of the load imparted by the jaws throughthe actuator arm. Additionally, the quick-release assembly of thepresent disclosure can allow for a quick and/or easy changing of jaws ona chuck. The quick-release assembly and/or the use of a non-splitunitary bearing can be provided in the form of a retro-fit kit to adaptexisting chuck assemblies to achieve the benefits of the quick-releaseassembly and/or the use of a non-split unitary bearing.

Further areas of applicability will become apparent from the descriptionprovided herein. It should be understood that the description andspecific examples are intended for purposes of illustration only and arenot intended to limit the scope of the present disclosure.

DRAWINGS

The drawings described herein are for illustration purposes only and arenot intended to limit the scope of the present disclosure in any way.

FIG. 1 is a perspective view of a chuck according to the presentdisclosure;

FIG. 2 is a top plan view of the chuck of FIG. 1;

FIG. 3 is another perspective view of the chuck of FIG. 1 showing thejaws uncoupled from the actuator arms;

FIGS. 4A and B are cross-sectional views along line 4-4 of FIG. 2showing the jaws in a retaining and releasing position, respectively;

FIG. 5 is an exploded assembly view of a first actuator arm assemblyaccording to the present disclosure utilizing a single-piece bearing anda first quick-release mechanism according to the present disclosure;

FIG. 6 is a perspective view of the single-piece bearing of FIG. 5;

FIG. 7 is a bottom plan view of the single-piece bearing of FIG. 6;

FIGS. 8A and B are enlarged fragmented cross-sectional views of thefirst actuator arm assembly along line 8-8 of FIG. 2 with thequick-release mechanism in a released and engaged position,respectively;

FIG. 9 is a fragmented exploded view of a second actuator arm assemblyutilizing a second quick-release mechanism according to the presentdisclosure;

FIGS. 10A and B are fragmented cross-sectional views of the assembledsecond actuator arm assembly along line 10-10 of FIG. 9 with the secondquick-release mechanism in a released and engaged position,respectively;

FIG. 11 is a fragmented exploded view of a third actuator arm assemblyutilizing a third quick-release mechanism according to the presentdisclosure;

FIGS. 12A and B are cross-sectional views of the assembled thirdactuator assembly along line 12-12 of FIG. 11 with the quick-releasemechanism in a released and engaged position, respectively; and

FIG. 13 is a fragmented cross-sectional view of a fourth actuator armassembly showing the use of a single retaining bolt to secure a jawthereto.

DETAILED DESCRIPTION

The following description is merely exemplary in nature and is notintended to limit the present disclosure, its application, or uses.

Referring to FIGS. 1-4, a workholding chuck assembly 20 according to thepresent disclosure is shown. The chuck 20 includes a housing subassembly22 that includes a main body 24 and an end plate 26 attached in asealing arrangement to a rear portion of the main body 24. A cavity 28is formed between the main body 24 and the end plate 26. An actuatorplate 30 is disposed in the cavity 28 and can move axially within thecavity 28 to allow the chuck 20 to retain and release workpieces asdescribed below.

The actuator plate 30 includes a front hub 32 that resides within acentral bore 34 in a front face 36 of the main body 24. A cover plate 38is disposed over the central bore 34 in the front face 36 to preventdebris and other contamination from entering into the cavity 28 and thehousing subassembly 22. The end plate 26 includes a central bore 40 thatis configured to receive a rear hub 42 of the actuator plate 30. In thismanner, the actuator plate 30 is supported for axial movement within thecavity 28 of the housing subassembly 22.

The end plate 26 and the main body 24 can include a plurality ofopenings 44, 45 that can be used to attach the housing subassembly 22 toan adaptor plate (not shown), which provides a proper bolt pattern forsecuring the chuck 20 to an appropriate lathe or other machiningapparatus (not shown).

A plurality of actuator arms 46 is arranged within the housingsubassembly 22 and can have a jaw 48 attached thereto. The actuator arms46 can pivot about an axis within the housing subassembly 22 to causethe jaws 48 to move radially to retain and release a workpiece asdescribed below. The actuator arms 46 are post-style arms that have agenerally cylindrical front portion 50, a generally cylindrical rearportion 52, and a semi-spherical middle portion 54. The front and rearportions 50, 52 are axially offset from one another (not axiallyaligned), as shown in FIG. 4. The rear portion 52 is disposed within arear bearing 56 having a generally semi-spherical exterior. The rearbearing 56 is disposed within an opening 58 in the actuator plate 30.The opening 58 has a concave inner periphery that is generallycomplementary to the generally semi-spherical exterior of the rearbearing 56. A key 60 prevents relative rotation between the rear portion52 and the rear bearing 56. The middle portion 54 of the actuator arm 46is disposed in a front bearing 66. The rear bearing 56 and thesemi-spherical middle portion 54 of the actuator arm 46 are on a samefront-rear center line (not shown). An end cap 70 and a spring 72 aredisposed in a central bore 74 in the rear portion 52 of the actuator arm46. The spring 72 biases the end cap 70 rearwardly and rides along thefront surface of the end plate 26. The end cap 70 and the spring 72thereby bias the actuator arm 46 forwardly and against the front bearing66. The interior bore of the rear bearing 56 is offset and angled suchthat axial movement of the actuator plate 30 and the rear bearing 56causes the actuator arm 46 to pivot within the front bearing 66 throughan angle α relative to a front-rear center line of the front bearing 66,as shown in FIG. 4B. This pivoting motion of the actuator arms 46 movesthe jaws 48 radially between a retaining position, as shown in FIG. 4A,and a releasing position, as shown in FIG. 4B, to grasp and release aworkpiece, respectively.

Referring now to FIGS. 4-8, the actuator arm 46 is maintained within thechuck 20 by a front bearing assembly 80, which is secured to a steppedaxial bore 82 in the front face 36 of the main body 24. The frontbearing assembly 80 includes the front bearing 66, a seal ring assembly84, and a plurality of retaining fasteners 86.

The front bearing 66 is a unitary non-split bearing that retains theactuator arm 46 within the housing subassembly 22. The front bearing 66includes a generally circular front flange portion 94 and a generallycylindrical rear portion 96 extending rearwardly from the flange portion94. The front bearing 66 is disposed within a stepped bore 82 in thefront face 36 of the main body 24. The flange portion 94 includes aplurality of openings 100 that can receive fasteners 86 to secure thefront bearing 66 to the housing subassembly 22. The front bearing 66includes a central through opening 101 within which the actuator arm 46is disposed. The central opening 101 includes an annular channel 102 inthe flange portion 94 within which the seal ring assembly 84 isdisposed. The seal ring assembly 84 includes a generally U-shapedannular member 104 with an annular spring 106 disposed therein. Theannular spring 106 helps maintain contact between the annular member 104and the exterior surface of the actuator arm 46 so as to retain greasewithin the front bearing 66.

The central opening 101 in the rear portion 96 of the front bearing 66includes a front annular section 110 having a first radius and a rearannular section 112 rearward of the front annular section 110 having asecond radius. The first and second radii can be the same. The first andsecond radii centers can be different. The rear portion 96 includes twoaxially extending pockets 116 that are spaced 180° apart. The pockets116 are extended radially into front and rear sections 110, 112 to allowthe semi-spherical middle portion 54 of the actuator arm 46 to bedisposed therein, as described below.

Each pocket 116 includes a radial recess 118 that extends axially alongthe pocket 116. The recesses 118 work in conjunction with a homingmechanism 120 to allow limited rotational movement between the actuatorarm 46 and the front bearing 66, as described below.

The rear portion 96 includes a removable wall portion 122 that formspart of one of the pockets 116 and includes the associated recess 118.The removable wall portion 122, as best seen in FIG. 7, includes convexsidewalls 124 that engage with complementary concave sidewalls 126 inthe rear portion 96. Engagement between the convex sidewalls 124 and theconcave sidewalls 126 radially secures the removable wall portion 122within the rear portion 96. As a result of this engagement, theremovable wall portion 122 is removed by axial movement relative to therear portion 96. A set screw 128 (shown in FIG. 5) axially retains theremovable wall portion 122 within the rear portion 96.

The semi-spherical middle portion 54 of the actuator arm 46 has a pairof opposing flats 132 that are spaced 180° apart with spherical surfaces134 therebetween. The flats 132 allow the actuator arm 46 and the middleportion 54 to be inserted into the front bearing 66. Specifically, toinsert the actuator arm 46 into the front bearing 66, the flats 132 arealigned 90° out of phase with the pockets 116 in the front bearing 66.With this alignment, spherical surfaces 134 are aligned with the pockets116. This alignment allows the middle portion 54 to axially slide intothe opening 101 and into the rear portion 96. Once the middle portion 54is within the rear portion 96 and engaged with the seal ring assembly84, the actuator arm 46 and/or the front bearing 66 can be rotated 90°relative to one another so that the flats 132 are now aligned with thepockets 116. With this alignment, the spherical surfaces 134 engage withthe front and rear sections 110, 112 of the rear portion 96 between thepockets 116. Engagement of the spherical surface 134 with the front andrear sections 110, 112 enable the actuator arm 46 to pivot within thefront bearing 66 to allow radial movement of the jaws 48 to grip andrelease a workpiece, as described below.

The middle portion 54 includes a radially extending through an opening136 that receives the homing mechanism 120. The homing mechanism 120allows limited relative rotation between the actuator arm 46 and thefront bearing 66. The homing mechanism 120 includes a pair of engagingmembers 140 having tapered tips 142, a spring 144, and a rod 146. Asbest seen in FIG. 8, the engaging members 140, the spring 144, and therod 146 are disposed in the opening 136 in the middle portion 54 of theactuator arm 46. The spring 144 biases the engaging members 140 radiallyoutwardly so that the tips 142 engage with the recesses 118 in the rearportion 96 of the front bearing 66. The rod 146 limits relative radialmovement of the engaging members 140 toward one another. The engagementof the tips 142 with the recesses 118 allows limited relative rotationbetween the actuator arm 46 and the front bearing 66 while biasing theactuator arm 46 toward an aligned home position within the front bearing66. This limited relative rotation facilitates the engagement of the jaw48 with a workpiece. Specifically, when clamping a workpiece in thechuck 20, the engagement of the jaws 48 with the workpiece may requiresome slight twisting of the jaws 48 relative to the workpiece to get afirm grip. This limited relative rotation is facilitated by the homingmechanism 120 associated with each actuator arm 46.

The removable wall portion 122 enables the homing mechanism 120 to beassembled in the opening 136. Specifically, when the actuator arm 46 isdisposed in the front bearing 66, as described above, a first one of theengaging members 140 is inserted through the opening 136. The spring 144and the rod 146 are then inserted into the opening 136. The otherengaging member 140 can then be inserted into the opening 136 andforcibly pushed toward the other engaging member 140 and held in placeagainst the force of the spring 144. The removable wall portion 122 canthen be axially inserted into the rear portion 96 and the engagement ofconcave and convex sidewalls 126, 124 prevents the home mechanism 120from coming out of the opening 136. The set screw 128 is then used toaxially secure the removable wall portion 122 to the rear portion 96.

The jaws 48 are attached to the front portions 50 of the actuator arms46. As shown in FIG. 5, the front portion 50 of the actuator arm 46 caninclude a pair of axially extending tangs 150. The tangs 150 can beoffset (eccentric) relative to an axially extending center line (notshown) of the front portion 50. The tangs 150 can engage withcomplementary offset recesses 152 in an interior stepped through a bore154 of the jaw 48. The jaw 48 includes a vent opening 156 to facilitatethe positioning/removing the jaw 48 on/from the actuator arm 46.Engagement of the tangs 150 with complementary offset the recesses 152in the jaw 48 prevents relative rotational movement between the jaw 48and the actuator arm 46.

According to the present disclosure, the jaws 48 can be removablysecured to the front portions 50 of the actuator arms 46 with aquick-release mechanism. A first quick-release mechanism 160, as bestseen in FIGS. 5 and 8, uses a central bore 162 in the front portion 50of the actuator arm 46 to secure the jaw 48 thereto. The central bore162 includes a radially extending annular channel 164 to facilitate theretaining of the jaw 48 to the actuator arm 46. The quick-releasemechanism 160 also includes an axially extending retaining member 166having a head 168 and a stem 170. A central bore 172 extends axiallythrough the retaining member 166. The central bore 172 includes a firstportion 174 adjacent the head 168 that has a first diameter and a secondportion 176 adjacent the end of a stem 170 having a second diameterlarger than the first diameter. The first portion 174 is threaded. Athreaded fastener 178 is disposed in the central bore 172 and engageswith the threads in the first portion 174. The quick-release mechanism160 also includes a first set of retaining balls 180 having a firstdiameter and a single actuating ball 182 larger than the retaining balls180. Three radially extending openings 184 extend through the stem 170adjacent its end. The openings 184 can be equally spaced about theperiphery of the stem 170.

The actuating ball 182 and the retaining balls 180 are disposed in thesecond portion 176 of the central bore 172 with the retaining balls 180aligned with the openings 184. The actuating ball 182 is disposedbetween the retaining balls 180 and an end 186 of the fastener 178.Retaining rings 188 (FIG. 8 only) can be disposed in the openings 184 toinhibit the retaining balls 180 from being pushed entirely through theopenings 184. Non-removing axial movement of the fastener 178 relativeto the retaining member 166 allows the quick-release mechanism 160 tosecure the jaw 48 to the actuator arm 46, as shown in FIG. 8B, andallows the jaw 48 to be removed from the actuator arm 46, as shown inFIG. 8A. Specifically, as shown in FIG. 8B, when the fastener 178 isrotated in the appropriate direction a few rotations relative to theretaining member 166, the end 186 pushes the actuating ball 182rearwardly into the retaining balls 180. This movement causes theretaining balls 180 to move radially outwardly into the openings 184 andprotrude beyond the outer periphery of the stem 170 and into the annularchannel 164. In this position, the retaining member 166 is secured tothe actuator arm 46 and thereby retains the jaw 48 on the actuator arm46.

When it is desired to remove the jaw 48 from the actuator arm 46, thefastener 178 is rotated the opposite direction relative to the retainingmember 166. With a few rotations of the fastener 178, the end 186 nolonger presses the actuating ball 182 against the retaining balls 180.The jaw 48 can then be pulled away from the actuator arm 46. The slopingnature of the annular channel 164 causes a radially inward force to beexerted on the retaining balls 180, thereby pushing the retaining balls180 into the stem 170. The movement of the retaining balls 180 back intothe stem 170 allows the jaw 48 to be removed from the front portion 50of the actuator arm 46.

Thus, the quick-release mechanism 160 enables the jaws 48 to be quicklyand easily attached to and removed from the actuator arms 46. thefastener 178 is not removed from the retaining member 166 during theoperation of the quick-release mechanism 160. Rather, a few simple turnsof the fastener 178 allows sufficient clearance between the end 186 andthe actuating ball 182 to allow the retaining member 166 to disengagefrom the actuator arm 46. Conversely, a few simple turns of the fastener178 in an opposite direction cause enough movement in the actuating ball182 to push the retaining balls 180 into the annular channel 164 andsecure the retaining member 166 to the actuator arm 46. Thequick-release mechanism 160 thereby provides an easy and efficient wayto change the jaws 48 so that the chuck 20 can be configured to receivedifferent workpieces.

Referring now to FIGS. 9 and 10, a second quick-release mechanism 200that can be used to secure the jaw 201 to an actuator arm 202 is shown.The middle and rear portions of the actuator arm 202 are substantiallythe same as that discussed above with reference to the actuator arm 46.As such, the middle and rear portions are not shown nor discussed. Afront portion 204 of the actuator arm 202, however, is different. Thefront portion 204 includes a central bore 206 that extends axially intothe actuator arm 202. A first portion 208 of the central bore 206adjacent the end is a radially elongated slot. A second portion 210 ofthe central bore 206 rearward of the first portion 208 is generallycylindrical. A third portion 212 is rearward of the second portion 210and is also cylindrical but has a diameter that is smaller than thesecond portion 210. A radially extending an annular channel 214 isdisposed in the second portion 210 of the central bore 206. Threestepped through openings 216 extend through the annular channel 214 tothe outer periphery of the front portion 204. The openings 216 can beequally spaced about the periphery of the front portion 204. Anotherthrough opening 218 extends through the front portion 204 and into thesecond portion 210 of the central bore 206 rearwardly of the openings216.

The quick-release mechanism 200 includes a spring 220 that is disposedin the third portion 212 of the central bore 206. A retaining member 222is disposed in each opening 216 of the central bore 206. The retainingmembers 222 each include a rounded inner head 224 and a stem 226extending therefrom having a rounded end 228. The stepped openings 216engage with the shoulder of the inner head 224 to prevent the retainingmembers 222 from passing entirely through the openings 216. A cammingmember 230 is disposed in the opening 218. The camming member 230includes a head 232 and a pin 234 extending therefrom. The pin 234 iseccentrically attached to the head 232 (i.e., the pin 234 is offset fromthe rotational axis of the head 232). The head 232 includes a toolrecess 236 that is configured to receive a tool therein to rotate thecamming member 230 within the opening 218. A snap ring 238 retains thecamming member 230 in the opening 218 and allows the camming member 230to non-removably rotate within the opening 218.

An actuating member 240 includes a head 242 and a stem 244 extendingtherefrom. The head 242 is complementary to a slotted first portion 208of the central bore 206. The stem 244 includes an end portion 246 thatis generally cylindrical with a diameter slightly smaller than thediameter of the second portion 210 of the central bore 206. A neckportion 248 of the stem 244 is disposed between the end portion 246 andthe head 242. The neck portion 248 has a diameter that changes betweenthe end portion 246 and the head 242 with a smallest diameter at ageneral midpoint location of the neck portion 248. The end portion 246includes a slot 250 on a periphery thereof. The slot 250 receives theeccentric pin 234 of the camming member 230. Rotation of the cammingmember 230 pushes on the slot 250, which, in turn, moves the actuatingmember 240 axially within the central bore 206.

The jaw 201 has an axially extending stepped bore 254 that is configuredto receive the front portion 204 of the actuator arm 202. A firstportion 256 of the bore 254 is circular and is complementary to theexterior of the front portion 204 of the actuator arm 202. A secondportion 258 of the bore 254 is slotted and is complementary to theslotted head 242 of the actuating member 240. The first portion 256 ofthe bore 254 includes a radially extending annular channel 260 that isconfigured to receive the ends 228 of the retaining members 222.

The quick-release mechanism 200 allows the jaw 201 to be easily andquickly secured to and removed from the actuator arm 202. Non-removingrotation of the camming member 230 moves the actuating member 240axially between a release position, as shown in FIG. 10A, and aretaining position, as shown in FIG. 10B. The spring 220 biases theactuating member 240 toward the retaining position. When thequick-release mechanism 200 is in the engaged position, as shown in FIG.10B, the jaw 201 is secured to the actuator arm 202 through theinteraction of the retaining members 222 and the annular channel 260.Specifically, the spring 220 biases the actuating member 240 forwardlytoward the jaw 201. As a result, the inner heads 224 of the retainingmembers 222 engage the end portion 246 of the actuating member 240. Thisengagement pushes the retaining members 222 radially outwardly such thatthe ends 228 engage with the annular channel 260. This engagementprevents the jaw 201 from being moved axially relative to the actuatorarm 202. Additionally, with the actuating member 240 in the engagedposition, the head 242 is disposed in the slotted second portion 258 ofthe stepped bore 254 and the jaw 201. The engagement of the head 242with the slotted second portion 258 prevents relative rotation betweenthe jaw 201 and the actuator arm 202. Thus, when in the engagedposition, the jaw 201 is secured to the actuator arm 202 and theactuator arm 202 can be pivoted to allow the jaws 201 to retain andrelease a workpiece.

When it is desired to remove the jaw 201, the camming member 230 isnon-removably rotated within the opening 218 with an appropriate tool.Rotation of the camming member 230 causes the pin 234 to push theactuating member 240 rearwardly within the actuator arm 202 against thebiasing force of the spring 220. The rearward movement of the actuatingmember 240 results in the inner heads 224 of the retaining members 222being aligned with the neck portion 248 of the actuating member 240, asshown in FIG. 10B. The jaw 201 can then be moved axially relative to theactuator arm 202. If the ends 228 of the retaining members 222 areprotruding into the annular channel 260, the tapering nature of theannular channel 260 and the rounded nature of the ends 228 cause aradially inward force on the retaining members 222 such that theretaining members 222 move radially inwardly and into engagement withthe neck portion 248 and allow the jaw 201 to be removed from theactuating arm 202. Once the jaw 201 has been removed from the actuatorarm 202, the user can release the camming member 230, which can resultin the actuating member 240 staying in place or moving forwardly underthe influence of the spring 220.

To attach the jaw 201 to the actuating arm 202, the camming member 230is rotated, if needed, to move the actuating member 240 rearwardly intothe actuating arm 202, which allows the retaining members 222 to bemoved radially inwardly. The rounded nature of the ends 228 can allowthe jaw 201 to push the retaining members 222 radially inwardly whenpositioning the jaw 201 on the front portion 204 of the actuator arm202. Once the jaw 201 is securely positioned on the actuator arm 202,the camming member 230 can be rotated to move the quick-releasemechanism 200 to the engaged position, as shown in FIG. 10A. In someinstances, the movement of the quick-release mechanism 200 from thedisengaged to the engaged position may be done entirely as a result ofthe influence of the spring 220 once the camming member 230 is releasedfrom being held in the disengaged position.

Thus, the second quick-release mechanism 200 according to the presentdisclosure can easily and quickly allow the jaws 201 to be attached toand removed from the actuator arms 202. It should be appreciated thatthe jaw 201 is shown as being a blank that can be machined to provide adesired gripping surface or features for retaining a workpiece therein.

Referring now to FIGS. 11 and 12, a third quick-release mechanism 300that allows quick and easy attachment/removal of a jaw 301 to/from anactuator arm 302 according to the present disclosure is shown. In thethird quick-release mechanism 300, the middle and rear portions of theactuator arm 302 are substantially the same as the middle and rearportions of the actuator arm 46 discussed above. As such, the middle andrear portions are not shown nor discussed. A front portion 304 of theactuator arm 302, however, is different. The front portion 304 isgenerally cylindrical and includes a radially inwardly extending recess306 therein. A plurality of through openings 308 extends through therecess 306 into a central bore 310 of the front portion 304. A ringmember 312 is configured to fit around the front portion 304 within therecess 306. The ring member 312 includes a plurality of tapered openings314 that align with the openings 308 in the recess 306. A plurality ofretaining balls 316 is disposed in the central bore 310 and can extendradially outwardly through the openings 308, 314. Radial movement of theretaining balls 316 relative to the openings 308, 314 allows the jaw 301to be secured to and removed from the actuator arm 302, as describedbelow.

An actuating member 320 includes a camming portion 322 having aplurality of generally cylindrical surfaces 324 with a plurality oframps 326 disposed therebetween. The ramps 326 have a radial dimensionthat changes between adjacent cylindrical surfaces 324, as best seen inFIG. 12. A stem 328 extends forwardly from the camming portion 322 andincludes a head 330 that can be engaged with a tool to non-removablyrotate the actuating member 320 within the actuator arm 302 as describedbelow.

An end plate 332 is configured to attach to the end of the front portion304 to secure the actuating member 320 and the retaining balls 316within the central bore 310 and to retain the ring member 312 on thefront portion 304 of the actuator arm 302. The end plate 332 can besecured to the actuator arm 302 with a plurality of fasteners 334. Theend plate 332 includes a central bore 336 through which the head 330 andthe stem 328 of the actuating member 320 extend. A pair of tangs 338extends from the end plate 332 and is offset from the central axis ofthe central bore 336. The tangs 338 engage with complementary offsetrecesses (not shown) at the end of a central bore 340 of the jaw 301 toprevent relative rotation between the actuator arm 302 and the jaw 301.

The central bore 340 of the jaw 301 includes a radially extendingannular channel 342. The annular channel 342 aligns with the openings308, 314 when the jaw 301 is positioned on the actuator arm 302.Non-removing rotation of the actuating member 320 relative to the jaw301 and the actuator arm 302 causes radial movement of the retainingballs 316 relative to the actuator arm 302 and the jaw 301 to allow thejaw 301 to be secured to and released from the actuator arm 302.

As shown in FIG. 12A, when the retaining balls 316 are engaged with theramps 326 of the actuating member 320, the retaining balls 316 do notextend into the annular channel 342. In this position, the jaw 301 canbe removed from or positioned on the actuator arm 302. To retain the jaw301 to the actuator arm 302, the actuating member 320 is rotatedrelative to the actuator arm 302 and the jaw 301. This relative rotationcauses the ramps 326 to push the retaining balls 316 radially outwardlythrough the openings 308, 314 and into the annular channel 342. Withsufficient rotation, the cylindrical surfaces 324 engage with theretaining balls 316 to provide the maximum radially outward position forthe retaining balls 316. In this position, the jaw 301 is axiallysecured to the actuator arm 302 by the retaining balls 316. The tangs338 prevent relative rotation between the jaw 301 and the actuator arm302.

To release the jaw 301, the actuating member 320 is rotated in theopposite direction so that the retaining balls 316 engage with the ramps326 and can move radially inwardly. The annular channel 342 can havesloped surfaces such that axial movement of the jaw 301 relative to theactuator arm 302 can exert a radially inward force on the retainingballs 316 to facilitate movement of the retaining balls 316 radiallyinwardly when releasing the jaw 301.

Thus, the third quick-release mechanism 300 according to the presentdisclosure can easily and quickly allow the jaws 301 to be secured toand removed from the actuator arms 302. Again, it should be appreciatedthat the jaw 301 is shown as a blank and can be machined to provide thedesired gripping features for the jaw 301.

Referring now to FIG. 13, a cross-sectional view of another way toretain a jaw 400 to a front portion 402 of an actuator arm 403 is shown.Specifically, the front portion 402 includes a threaded central bore404. A single-threaded fastener 406 can be secured in the central bore404 to retain the jaw 400 on the front portion 402. The front portion402 can include a pair of tangs 408 that are eccentric relative to anaxial center of the central bore 404. The tangs 408 can engage withcomplementary recesses at an end of a bore 410 in the jaw 400 to preventrelative rotation between the jaw 400 and the actuator arm 403. Thus, ifdesired, the single-threaded fastener 406 can be used to retain the jaw400 to the actuator arm 403. It should be appreciated, however, that theuse of the single-threaded fastener 406 does not provide thequick-release capability described above with reference to thequick-release mechanisms 160, 200, and 300. Further, the single-threadedfastener 406 is removed to change the jaw 400.

The quick-release mechanism and the unitary non-split upper bearing ofthe present disclosure can be used together or separately in new chuckassemblies or can be used together or separately to retrofit existingchuck assemblies not having these features. To facilitate this, kits canbe sold to upgrade the existing chuck assemblies. In particular, asshown in FIG. 5, a retrofit kit 500 can include the actuator arm 46, thehoming mechanism 120, the seal ring assembly 84, the front bearingassembly 80, the quick-release mechanism 160, and the jaw 48. The jaw 48can be provided as a blank to be machined by the purchaser for theparticular workpiece to be held or can be pre-machined in the desiredconfiguration to hold a workpiece. Optionally, the retrofit kit 500 caninclude the end cap 70 and the spring 72. It should be appreciated thatthe quick-release mechanism included in the retrofit kit 500 can be anyof the quick-release mechanisms described herein. Furthermore, ifdesired, in lieu of a quick-release mechanism, the retrofit kit 500 canbe configured to use a single-threaded fastener 406 to retain a jaw tothe associated actuator arm. Thus, the retrofit kit 500 can be used toretrofit an existing chuck assembly to provide the benefits of a unitarynon-split upper bearing and/or a quick-release mechanism and/or a singlefastener attaching method.

The workholding chuck according to the present disclosure is suitablefor use in a high-speed application. For example, the chuck according tothe present disclosure can be used on a lathe or other machiningapparatus that rotates the chuck assembly at speeds in excess of 3,000RPM. It should be appreciated, however, that the chuck assembly can beused on lower-speed applications, although all the benefits of thepresent disclosure may not be realized. Additionally, it should beappreciated that the quick-release mechanisms and the non-split unitaryfront bearing of the present disclosure can be used together orseparately. Additionally, the quick-release mechanisms and/or thenon-split unitary front bearing can be used with actuator arms that aredriven by other means than the actuator plate 30 disclosed herein. Forexample, the non-split unitary bearing and/or quick-release mechanism ofthe present disclosure can be used on an actuator arm disposed in anequalizing chuck, such as that shown in U.S. Pat. No. 6,655,699,entitled “Six Jaw Equalizing Chuck,” the disclosure of which isincorporated herein by reference. Moreover, while the present disclosureshows a chuck having three actuating arms and three jaws, it should beappreciated that more or less than three actuator arms and/or jaws canbe used. Thus, while the present disclosure has been described withreference to particular illustrations and figures, it should beappreciated that changes can be made to that shown without deviatingfrom the present disclosure. Thus, the description is merely exemplaryin nature and variations are not to be regarded as a departure from thespirit and scope of the present disclosure.

1. A workholding chuck assembly for holding a workpiece, the chuckassembly comprising: a housing having a front face; a plurality ofactuator arms in said housing, said actuator arms having a first endportion extending from said front face and operable to receive aworkpiece retaining jaw thereon, a second end portion in said housingand an intermediate portion between said first and second end portions,said intermediate portion including a semi-spherical section having atleast two semi-spherical surfaces with radially recessed surfacestherebetween; a plurality of non-split unitary bearings having a boretherethrough, each of said bearings being disposed around saidsemi-spherical section of said intermediate portion of an associated oneof said actuator arms, each bore having an engaging surface that engageswith said semi-spherical surfaces and at least two radially recessedpockets; and at least one actuator coupled to said second end portionsand operable to drive pivotal movement of said actuator arms in saidbearings to retain and release a workpiece.
 2. The workholding chuckassembly of claim 1, wherein said radially recessed surfaces of saidsemi-spherical section are aligned with said radially recessed pocketswhen said actuator arms pivot to retain and release a workpiece.
 3. Theworkholding chuck assembly of claim 2, wherein engagement of said boreengaging surface with said semi-spherical surfaces of saidsemi-spherical sections limit axial movement between said actuator armsand said bearings.
 4. The workholding chuck assembly of claim 2, whereinsaid radially recessed surfaces of said semi-spherical section and saidradially recessed pockets allow said semi- spherical section to beinserted into said bore of an associated one of said bearings.
 5. Theworkholding chuck assembly of claim 1, wherein said bore engagingsurface of each of said bearings includes a first axially curvingannular section having a first radius of curvature and a second axiallycurving annular section having a second radius of curvature differentthan said first radius of curvature.
 6. The workholding chuck assemblyof claim 1, wherein said bearings are mounted to said front face of saidhousing.
 7. The workholding chuck assembly of claim 1, furthercomprising a plurality of homing mechanisms each coupled to one of saidactuator arms, each of said homing mechanisms engaging with said boreengaging surface of an associated bearing and allowing limited relativerotation between said actuator arm and said bearing and biasing saidactuator arm to a predetermined orientation relative to said bearing. 8.The workholding chuck assembly of claim 7, wherein each of said bearingsincludes a removable wall portion that forms a portion of said bore,said removable wall portion engaging with said homing mechanism.
 9. Theworkholding chuck assembly of claim 1, further comprising a quick-release mechanism operable to selectively attach and detach workpieceretaining jaws from said actuator arms.
 10. A workingholding chuckretro-fit kit comprising: an actuator arm having a first end portionoperable to receive a workpiece retaining jaw thereon, a second endportion operable to be coupled to a chuck actuating member, and anintermediate portion between said first and second end portions, saidintermediate portion including a semi-spherical section having at leasttwo semi-spherical surfaces with radially recessed surfacestherebetween; and a non-split unitary bearing having a bore therethroughwith an engaging surface and at least two radially recessed pockets,said bearing being disposable around said semi- spherical section ofsaid intermediate portion of said actuator arm with said bore engagingsurface engaging with said semi-spherical surfaces.
 11. The retro-fitkit of claim 10, wherein said radially recessed surfaces of saidsemi-spherical section are aligned with said radially recessed pocketswhen said actuator arm is operatively disposed in said bearing.
 12. Theretro-fit kit of claim 11, wherein said radially recessed surfaces ofsaid semi-spherical section and said radially recessed pockets allowsaid semi-spherical section to be inserted into said bore of saidbearing.
 13. The retro-fit kit of claim 10, further comprising a jawoperable to be coupled to said first end portion of said actuator arm.14. The retro-fit kit of claim 13, further comprising a quick-releaseassembly having at least one retaining member operable to selectivelysecure said jaw to and allow removal of said jaw from said actuator armthrough non-removing movement of a component of said quick-releaseassembly coupled to said retaining member.